In enclosures of large sizes, such as rooms where electrical equipment is stored, it is essential that quick and total evacuation of the fire extinguishing medium be effected so as to establish in the entire room an atmosphere in which combustion cannot take place. One evident solution is to install a great number of receptacles storing the pressure medium with a common discharge manifold or delivery line. However, the installation of such a system is extremely costly in addition to taking considerable space. Indeed, each cylinder must be separately equipped with valves, rupture disks and pressure gages, thereby requiring individual maintenance. Furthermore, where a large size room may require a hundred or so of these receptacles, it is to be noted that filling time for each with the medium takes, as an average, over one hour.